As of PostgreSQL 13, changes to the fundamental replication
configuration can be applied with a simple SIGHUP, no restart
required.
In case the old behaviour is desired, i.e. a full restart to apply
the configuration changes, the new configuration parameter
"standby_follow_restart" can be set. This parameter has no effect
in PostgreSQL 12 and earlier.
In certain corner cases, it's possible repmgrd may end up monitoring
a standby which was a former primary, but the node record has not
yet been updated.
Previously repmgrd would abort the promotion with a cryptic message
about being unable to find a node record for node_id -1 (the
default value for an unknown node id).
This commit addes a new configuration option "always_promote", which
determines whether repmgrd should promote the node in this case.
The default is "false", to effectively maintain the existing behaviour.
Logging output has also been improved to make it clearer what has
happened when this situation occurs.
Add notes to the documention mentioning that after postgres or repmgr
upgrades (postgres major upgrades), there are some changes that need
to be taken care of.
Signed-off-by: Martín Marqués <martin.marques@2ndquadrant.com>
From PostgreSQL 13, the "CREATE EXTENSION ... FROM" syntax is no longer
available. It's unlikely at this point that someone will find themselves
with a PostgreSQL 13 database and the legacy repmgr schema, but we'll
cover all bases just in case.
Commit 0574279 set the file permissions to 0600 rather than the user's
umask, but if initdb was executed with -g/--allow-group-access, the
file is maintained with 0640, so we'll just maintain the existing
permssions.
We have a --downstream option to check for attached nodes, but it
would be useful to have a corresponding --upstream option too.
A following patch will adapt the behaviour of this option when executed
on the primary node.
This is mainly useful for the --data-directory-config option, which
requires permission to read pg_settings to verify that the data
directory configured in "repmgr.conf" matches the data directory
actually in use.
If pg_settings read permission is not available, repmgr will fall
back to a simple check that the data directory configured in
"repmgr.conf" is a valid PostgreSQL directory. This is not entirely
foolproof, as it's possible PostgreSQL could be using a different
data directory.
